[alsa-devel] [PATCH v3 0/2] ALSA: Add PCM USER_PVERSION ioctl

[Takashi Iwai]

On Tue, 27 Jun 2017 13:43:43 +0200,
Takashi Sakamoto wrote:
> 
> Hi,
> 
> On Jun 27 2017 19:29, Takashi Iwai wrote:
> > Hi,
> >
> > this is a revised patchset that is applied on top of the current
> > for-next branch, in order to optimize the appl_ptr sync on x86-64,
> > adapting the alsa-lib side change by Sakamoto-san's patchset.
> >
> > Basically it adds a new ioctl for receiving the supported PCM protocol
> > version from user-space side, and change the mmap code to allow only
> > disabling the PCM status record depending on the supported protocol
> > version.  The former patch is identical with the previous version,
> > only the latter one differs.
> >
> > The corresponding alsa-lib patch will follow.
> >
> >
> > thanks,
> >
> > Takashi
> >
> > ===
> >
> > Takashi Iwai (2):
> >    ALSA: pcm: Add an ioctl to specify the supported protocol version
> >    ALSA: pcm: Disable only control mmap for explicit appl_ptr sync
> >
> >   include/sound/pcm.h         |  1 +
> >   include/uapi/sound/asound.h |  3 ++-
> >   sound/core/pcm_compat.c     |  1 +
> >   sound/core/pcm_native.c     | 29 ++++++++++++++++++++++++-----
> >   4 files changed, 28 insertions(+), 6 deletions(-)
> 
> Reviewed-by: Takashi Sakamoto <o-takashi at sakamocchi.jp>
> 
> I note that the idea of USER_PVERSION ioctl is itself worth for the
> other interfaces/protocols such as control. In the
> interfaces/protocols, many structures have reserved members. As
> Iwai-san described in the first patch, when changing them to utilize
> these reserved members, this idea is a solution to balance
> compatibility and extensibility.

OK, let's go with this.  I'll merge this and also the alsa-lib
patchsets.


Thanks!

Takashi